Question: The bacteria in a jar triple every 20 seconds. After three minutes, there are 275,562 bacteria in the jar. How many were in the jar at the beginning of the experiment?
Solution: After three minutes, the number of bacteria $n$ has tripled $9$ times.  This gives us the equation $n \cdot 3^9 = 275,\!562$, or $19,\!683n=275,\!562$, so $n = \boxed{14}$